1. Field of the Invention
The present invention relates to semiconductor devices, and, more particularly, to a method and circuit for automatically reducing power consumption in a semiconductor device without the use of external logic or a dedicated pin.
2. Discussion of Related Art
Electrical products of today quite often incorporate semiconductor devices due to their many advantages. The use of such devices has enabled electrical products to accomplish tasks more quickly and efficiently than was previously possible. In an effort to continually improve such products, a desired goal has been to reduce the amount of power consumed during the operation of the products. Towards this end, it is desirable to reduce the power consumption of a product's component parts, including any semiconductor devices. One way to accomplish this goal is to "power down" the semiconductor device when the device is in a predefined state, such as an inactive state, so that the semiconductor device draws a reduced amount of current, and therefore, consumes less power.
One approach taken in the art to power down a semiconductor device is to pass a signal to the device over a dedicated pin or combination of dedicated pins, which signal directs the device to power down. A second approach taken in the art is to use a dedicated serial port or other communication scheme to direct a power down command word to the semiconductor device. The power down command word is then decoded, wherein the device is powered down. A significant problem with both of these approaches is that they require the use of at least one dedicated pin of the semiconductor device to accomplish the power down function. Oftentimes, a dedicated pin is unavailable because all of the pins on the semiconductor device are used to perform other functions. Thus, a "power down" mode cannot be implemented on such devices using prior technology. In addition, there are often situations where all existing input states of a semiconductor device are reserved for other functions. The effect of this situation is the same--no power down mode can be implemented on such devices using prior technology.
Accordingly, there is a need to provide a system for powering down a semiconductor device that minimizes or eliminates one or more of the problems set forth above.